Goodwill and Intangible Assets - Goodwill by Reporting Unit (Details) $ in Thousands	12 Months Ended
	Jan. 28, 2018 USD ($)
Goodwill [Roll Forward]
Beginning balance	$ 329,703
Additions	12,194
Ending balance	341,897
Signal Integrity
Goodwill [Roll Forward]
Beginning balance	261,891
Additions	12,194
Ending balance	274,085
Power and High Reliability
Goodwill [Roll Forward]
Beginning balance	49,384
Additions	0
Ending balance	49,384
Wireless and Sensing
Goodwill [Roll Forward]
Beginning balance	18,428
Additions	0
Ending balance	$ 18,428